Absorption type refrigerating system



A. R. THOMAS 1,976,202

ABSORPTION TYPE REFRIGERATING SYSTEM Get. 9, 1934.

Filed D60. 21, 1932 0 H INVEETOR.

BY W

ATTORNEY.

Patented @ct. 9, 1934 UNiED STATES PATENT OFFICE ABSGRPTION TYPE REFRIGERATING SYSTEM Albert R. Thomas, New York, N. Y., assignor to Electrolux Servel Corporation, New York, N. Y., a corporation of Delaware In air cooled refrigerating systems of this type,

it is highly desirable for best operating efliciency to have the internal pressure vary with the temperature of the cooling air. Since the air temperature is subject to wide variation, if the pressure is fixed to correspond with the most extreme temperature, the advantage of lower condensing pressure required under average conditions is sacrificed. The condensing pressure necessary under average conditions allows high thermal efficiency and the corresponding low boiler temperature reduces the rate of internal corrosion.

It has heretofore been proposed to provide an enlarged chamber in the condenser vent line for the storage of excess auxiliary fluid which is displaced into the gas circuit upon rise in the condenser temperature. It is a purpose of this invention to use such a storage chamber, herein referred to as a pressure vessel, and effect a greater variation in pressure without increasing the volume or size of the vemel.

It is further among the objects of this invention to effect a more rapid changein pressure and utilize the storage or pressure vessel as an extension of the condenser so that it functions as such at high ambient temperatures when it is filled principally with refrigerant vapor.

The type of refrigeration system under consideration comprises, in general, an'evaporator and an absorber connected in a circuit for an inert gas as an auxiliary pressure equalizing fluid. From a generator containing a solution of refrigerant in a liquid absorbent, liquid refrigerant is distilled off and conveyed to the evaporator, and the resulting weak solution is circulated through the absorber. In the evaporator, the liquid refrigerant evaporates while diffusing into the inert gas, and in the absorber, refrigerant vapor is absorbed out of the inert gas into solution with the absorbent. The above mentioned-objects of my invention may be attained by providing an auxiliary circuit communicating with the inert gas circuit in such a manner that there circulates in the auxiliary circuit an excess quantity of inert gas which, due to circulation thereof during normal operation of the system, is at substantially the same partial pressure as gas flowing from the absorber to the evaporator. Suitable provision is made for automatically displacing gas from the auxiliary circuit into the main circuit to increase the pressure in the latter, and thus the total pressure in the system.

The nature of my invention and the objects and advantages thereof will be more fully understood from consideration of the following description taken in connection with the accompanying drawing in which the figure shows schematically a refrigerating system of the pressure equalized absorption type embodying the present invention;

The refrigerating system shown in the drawing is similar to that disclosed in my copending application Serial No. 613,387. Briefly, in the generator 10 a refrigerant vapor is expelled from solution in an absorption liquid by heat. For purposes of description, ammonia may be the re- 7 frigerant .and water the absorbent. Ammonia vapor from the upper part of the generator 10 flows in conduit 12 through a rectifier 11 to the upper part of a separating vessel 13. The latter flowing inconduit 12. From the separator, the vapor passes to an air cooled condenser 14 where it is liquefied, the liquid flowing through conduit 15 into the upper part of a vessel 16. From the lower part of vessel 16, liquid ammonia flows 0 through conduit 17 to the absorber cooling coil 18 which is constructed and arranged to constitute thermosiphon conduit.

Cooling of the absorber is accompanied by vaporization of some of the ammonia in coil 18, the vapor raising liquid'ammonia upwardly through conduit 19 back to the separator 13 by thermosiphonic or gas lift action. The lifting vapor then passes back into the condenser and the liquid ammonia which accumulates in the lower part of the separator 13 overflows through conduit 20 into the evaporator 21 where it evaporates by diffusion into an auxiliary pressure equalizing fluid such as hydrogen which circulates between the absorber 22 and the evaporator 21 by way of the gas heat exchanger 23.

Weak absorption liquid flows from the lower part of the generator 10 through a liquid heat exchanger 24 to the absorber 22 where it absorbs ammonia out of the gas mixture. absorption liquid accumulates in the lower part of the absorber from where it flows back to the generator 10 through the liquid heat exchanger 24, being raised from the surface level of liquid in the absorber to the surface level of liquid in the generator by a thermosiphon or gas lift element 25 due to vapor formed by heating the lower .part of the element in a well known manner.

In accordance with the present invention, there ,is provided a closed vessel 26 connected to the The enriched gas circuit through conduits 27 and 28. These connections, as shown, are made to the gas heat exchanger, conduit 27 connecting the upper end of the pressure vessel 26 to the weak gas portion of the circuit and conduit 28 connecting the lower end of the pressure vessel to the "rich gas portion of the circuit. The path formed by conduit 27, pressure vessel 26, and conduit 28, in this embodiment, is in effect a shunt across the gas circuit between the evaporator and absorber. It is apparent, however, that conduit 2'7 may be connected either to the weak or rich side of the gas circuit. A connection to the weak gas side will be more effective in increasing the amount of hydrogen stored in the auxiliary circuit at low room temperature, as hereinafter set forth, but on the other hand connection to the rich gas side is more desirable in preventing the possibility of introducing ammonia vapor into the weak gas when the unit is operating near maximum pressure.

In a condenser vent chamber as heretofore proposed, the amount of hydrogen at low air temperatures is from 30-40% of the chamber volume as the temperature difference between the condenser and chamber is only around 15 C. In

.the gas circulation circuit of the refrigerating system there is a gas mixture containing more than 90% hydrogen and by providing in connection with the condenser vent chamber or pressure vessel 26, an auxiliary circuit communicating with the gas circuit, there circulates through thepressure vessel, when condensation is not taking place therein, this gas mixture which is nearly all hydrogen.

Circulation occurs upwardly through conduit 27 and downwardly through conduit 28 due to the greater speciflc weight of the gas in the pressure vessel 26 and conduit 28 than that in conduit 27. When the concentration of hydrogen in the pressure vessel 26 approaches that in the gas circuit, circulation becomes very slow, that is, just enough to remove the excess ammonia vapor coming from the residual gases in condensation.

As the air temperature increases and the pressure becomes insuflicient for complete condensation, the excess ammonia vapor flows through conduit 29, conduit 28, and 'a liquid trap 30 to the absorber. Conduit 29 constitutes a vent from the condenser to the auxiliary circuit 26, 2'7, 28, 30. Since conduit 28 and the trap 30 are exposed to the air, condensation of the ammonia vapor occurs and the liquid collects in the trap stopping circulation in this direction causing the ammonia vapor to flow into the pressure vessel 26 displacing the hydrogen therefrom through conduit 27 into the gas circuit, thus increasing the pressure in the latter. During high ambient temperature the pressure vessel 28'functions as a continuation of the condenser, the condensate draining through conduit 29 to the vessel 18 where it Joins refrigerant liquid flowing toward the evaporator.

Whenthetempcratureoftheairagaindecreases, no longer occurs in conduit 28 and the liquid ammonia evaporates from the trap 30 by diflusim into the gas system. when the trap opens, circulation through the pressure vessel is again established. as described above. 7

Itwillbeobvioustothoocskilledintheart thatvsriousotherchangesmaybe madeinthe construction and arrangement without departing from the spirit of the invention and thereforetheinvcntionisnctlimitedtowhstisllim' in the drawing and described in the specification but only as indicated in the following claims.

What is claimed is, v

l. The method of refrigerating with a system containing a refrigerant fluid'and an additional fluid for equalizing pressure which includes, circulating an excess of said additional fluid under normal operating conditions in an auxiliary circuit communicating with said system in such manner that said excess fluid is maintained at substantially the same concentration as the additional fluid in the system, and transferring additional fluid from said auxiliary circuit into said system when the pressure in the latter increases.

2. The method of refrigerating with a system containing a refrigerant fluid and an additional fluid for equalizing pressure which includes, circulating an excess of said additional fluid under normal operating conditions in an auxiliary circuit communicating with said system in such manner that said excess fluid is maintained at substantially the same concentration as the additional fluid in the system, and introducing refrigerant fluid into said auxiliary circuit to displace additional fluid therefrom into said system when the pressure in the latter increases.

3. The method of refrigerating with a system containing a refrigerant fluid and an additional fluid for equalizing pressure which includes, circulating an excess of said additional fluid under normal operating conditions in an auxiliary circuit communicating with said system, and introducing refrigerant fluid from said system into said circuit and decreasing circulation in said circuit upon increase of pressure in the system whereby excess additional fluid is displaced into said system.

4. The method of refrigerating which includes,

circulating an auxiliary fluid in a continuous circuit, evaporating cooling fluid by diffusion in one portion of said circuit, absorbing cooling fluid out of the resulting gas mixture in another portion of said circuit, flowing an excess of said auxiliary fluid in a path shunting the absorbing m rator and absorber, evaporating cooling fluid by diffusion in said evaporator, absorbing cooling fluid out of the resulting gas mixture in said absorber, circulating an excess of said auxiliary fluid in a second circuit communicating with ond circuit and introducing cooling fluid therein to displace excess auxiliary fluid into the first said circuit responsive to increase of pressure in the latter.

first said circuit, and decreasing flow in said sec- 6. A refrigerating system including, agenerao tor, a condenser, an evaporator, and an absorber interconnected for the circulation of a cooling fluid, said evaporator and absorber being interconnected in a continuous circuit for an auxiliary fluid, a second .circuit for an excess of auxiliary fluid communicating with the first said circuit, a vent'connection from the discharge end of said' condenser to said second circuit, and means for stopping circulation in said second circuit re-. sponsive to rise oi pressure in the system.

7. A refrigeration system comprising a generator, air cooled condenser, evaporator, and absorber connected for circulation of refrigerant fluid, said evaporator and absorber being interconnected to form a main circuit for inert gas, means forming an auxiliary circuit for inert gas branching from said main circuit, a vent from said condenser connected to said auxiliary circuit, the highest point of said auxiliary circuit being in one portion thereof between said vent connection and said main circuit, an enlarged chamber in said portion, a liquid drain from said chamber to the path of liquid refrigerant fluid from said condenser to said evaporator, and a seal-forming liquid trap in the other portion of said auxiliary circuit, said chamber and second portion of the auxiliary circuit being cooled by air.

8. A refrigeration system comprising a generator, air cooled condenser, evaporator, and ab-' sorber connected for circulation of refrigerant fluid, said evaporator and absorber being interconnected to form a main circuit for inert gas, means forming an auxiliary circuit for inert gas branching from said main circuit, a vent from said condenser connected to said auxiliary circuit, the highest point of said auxiliary circuit being in one portion thereof between said vent connection and said main circuit, a gas storage chamber in said portion, and a seal-forming liquid trap in the other portion of said auxiliary circuit, said other portion being cooled by air.

9. A refrigeration system comprising a generator, air cooled condenser, evaporator, and absorber connected for circulation of refrigerant fluid, said evaporator and absorber being interconnected to form a main circuit for inert gas, means forming an auxiliary circuit for inert gas branching from said main circuit, a vent from said condenser connected to said auxiliary circuit, the highest point of said auxiliary circuit being in'one portion thereof between said vent connection and said main circuit, and a sealforming, liquid trap in-the other portion of said auxiliary circuit, said other portion being cooled by air.

10. A refrigeration system comprising a generator, condenser, evaporator, and absorber connected for circulation of refrigerant fluid, said evaporator and absorber being interconnected to form a main circuit for inert gas, means forming an auxiliary circuit for inert gas branching from said main circuit, a vent from said condenser connected to said auxiliary circuit, the highest point of said auxiliary circuit being in one portion thereof between said vent connection and said main circuit, and a seal-forming liquid trap in the other portion of said auxiliary circuit.

11. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid for equalizing'pressure, an air cooled condenser, a main circuit for said additional fluid, an auxiliary circuit for excess additional fluid branching from said main circuit, a vent from said condenser connected to said auxiliary circuit, the highest point of said auxiliary circuit being in one portion thereof between said vent connection and said main circuit, an enlarged chamber in said portion, and a seal-forming liquid trap in the other portion of said auxiliary circuit, said other portion being cooled by air.

12. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid for equalizing pressure, a condenser, a main circuit for said additional fluid, an auxiliary circuit for excess additional fluid branched from said main circuit, a vent from said condenser connected to said auxiliary circuit, the highest point of said auxiliary circuit being in one portion thereof between said vent connection and said main circuit, and a seal-forming liquid trap in the other portion of said auxiliary circuit.

13. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid for equalizing pressure, a condenser, a main circuit for additional fluid having a branch circuit for excess additional fluid, a vent from said condenser connectcd to said branch circuit, anupward loop in said branch circuit on one side of' said vent connection thereto. and a'seal-forming liquid trap in said branch circuit on the other side of saidvent connection. 7

14. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid for equalizing pressure, a condenser, a main circuit for additional fluid having a branch circuit for excess additional fluid, a vent from said condenser connected to said branch circuit, an upward loop in said branch circuit on one side of said vent-connection thereto, an enlarged chamber in the upward loop side of said branch circuit, and a seal-forming liquid trap in said branch circuit on the other side of said vent connection.

15. In an absorption refrigeration system con- *taining a refrigerant fluid and an additional fluid for equalizing pressure, an air cooled condenser, a main circuit for additional fluid having a branch circuit for excess additional fluid, a vent from said condenser connected to said branch circuit, an upward loop in said branch circuit on one side of said vent connection thereto, and a seal-forming liquid trap in said branch circuit on the other side of said vent connection, the latter being cooled by air.

16. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid for equalizing pressure, a main circuit for the additional fluid, an auxiliary circuit for excess additional fluid branched from said main circuit, and means for displacing additional fluid from said auxiliary circuit into said main circuit including means for stopping circulation in said auxiliary circuit.

17. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid ditional fluid from said auxiliary circuit into said main circuit including means for stopping circulation in said auxiliary circuit.

18. In an absorption refrigeration system containing a refrigerant fluid and an additional fluid for equalizing pressure, a main circuit for the additional fluid, an auxiliary circuit for excess additional fluid branched from said main circuit, and means utilizing refrigerant fluid for displacing additional fluid from said auxiliary circuit into said main circuit including a seal-forming liquid 14g trap for stopping circulation in said auxiliary circuit.

' 19. In an absorption refrigeration system con-- taining a refrigerant fluid and an additional fluid for equalizing pressure, a main circuit for the additional fluid, an auxiliary circuit for excess additional fluid branched from said main circuit, a storage chamber in said auxiliary circuit, and means for displacing additional fluid from said auxiliary circuit into said main circuit including 153 means for stopping circulation in said, aiuriliary circuit.

20. In an absorption refrigeration system contcining a refrigerant fluid and an additional fluid for equalizing pressure, a condenser, a main circuit for said additional fluid, an auriliary circuit for excess additional fluid branched from said main circuit, a vent from said condenser to said auxiliary circuit, and means for topping eircula= tion in said auxiliary circuit upon increase "eniperature of said condenser.

21. In an absorption refrigeration system containing a refrigerant fluid and an additional tor equalizing pressure, an air cooled condenser, main circuit for said additional fluid, an. an; cry circuit for excess additional fluid branched from main circuit, a vent from said condenser to said auxiliary circuit, and means for stopping cir culation said auxiliary circuit upon incre in temperature of the air.

22. In an absorption. refrigeration system con refri e ant fluid and an additional fiuid for equalizing pressure, on air cooled condenser, "rain circuit for said additional i'ir' an aux v circuit for excess additional fluid branched .nom said main circuit, a vent from said condenser to said auxiliary circuit, and. a sealforming liquid trap in said auxiliary circuit e2- posed for air cooling to stop circulation upon increase in temperature of said condenser.

23. In an absorption refrigeration system containing a refrigerant fluid ancl'an additional fluid for equalizing pressure, an air cooled condenser, a main circuit for said additional fluid,

an auxiliarycircuit for excess additional fluid branched from said main circuit, an enlarged chamber in said auxiliary circuit, a vent from said condenser to said auxiliary circui", and a seal-forming liquid trap in said auxiliary circuit exposed for air cooling to stop circulation upon increase in temperature of said condenser.

24. That improvement in the art of reirigera tion with a system containing a refrigerant fluid and an auxiliary gas for equalizing pressure which comprises storing an excess of said gas at sub rot/aces comprises storing an excess of said gas at sub stantially the same partial pressure as that of gas in the system under normal operating conditlons, displacing said excess by refrigerant fluid when the pressure L). the syse circulating the displaced gas in ti method of refrigera imclude circulating a pressure eouajzing gas in continuous circuit, evaporating gerant iluicl one portion of said circuit, abso hing eii'ige;- fluid in another portion of said circuit, storing an excess of pressure equalizing at sucstantielly the same partial pressure as that of gas in said circuit during normal operating conditions, and circulating the stored in said circuit upon crea e of pressure.

That improvement in the art of regrigeration by evaporation of refrigerant fiuil into a VJOlllZlZ quantity of inert gas which comprises maintaining an auxiliary quantity of inert gas at I substantiall the same partial pressure as that of gas in said working quantity during normal operating conditions and adding to the working quantity from said auxiliary quantity to increase the pressure of the former.

28. Tue method of refrigeration which includes circulating a pressure equalizing fluid in two continuous circuits having a portion in common, evaporating refrigerant fluid in one portion 01' the first of said circuits, absorbing refrigerant fluid in another portion of said circuit, and introducing refrigerant vapor into the second of said circuits and stopping circulation therein to displace pressure equalizing gas into said first circuit to increase the pressure in the latter.

ALBERT R. THOMAS.

gas 

